Reducing energy barriers by multi-interface design on MXene with confined Fe-doped CoSe2 for ultra-efficient OER electrocatalysis

To design multi-heterointerfaces for doping-type electrocatalysts is a promising strategy to synergistically balance the catalytic activity/durability. In this study, we report a dual-MOFs/MXene composite derivation strategy to construct porous N-doped carbon encapsulating Fe-doped CoSe2 on both sides of MXene (Fe-CoSe2@PNC/TC). Combining multi-characterizations and density functional theory calculations, the Fe doping and well-designed multi-interfaces can induce the internal Se vacancy and electronic structure modulation, increasing and enhancing the active sites and, thus, reducing energy barriers for oxygen evolution reaction (OER). Thereby, the OER activities of Fe-CoSe2@PNC/TC powder materials have been significantly improved, which exhibits an overpotential of only 244 mV to attain 10 mA cm−2 with the long-term durability and a ultra-small Tafel slope of 41.1 mV dec−1 in 1.0 M KOH electrolyte (No IR correction), far outperforming the benchmark of commercial IrO2. This work proposes a controllable route combining multi-interface design and heteroatom doping for ultra-efficient OER electrocatalysis.